1. Field of the Invention
The present invention relates to a color plasma display panel(called "PDP"), and more particularly, to a top electrode in a color plasma display panel which has a large discharge region between a sustain electrode and a scan electrode.
2. Discussion of the Related Art
Being one of luminous devices for displaying an image using a gaseous discharge in a cell, the PDP, in general, is spot lighted as an image display device directed to a large sized, direct view type image display device, particularly to an HDTV (High Definition TeleVision) era because it has a very simple fabrication process, easy to fabricate a large sized device and has a fast response.
FIG. 1 illustrates a cross section of a unit cell of a background art PDP, wherein, for convenience of understanding, sustain electrodes 11 and 11' on the top glass substrate 10 are turned at 90.degree. from a direction of an address electrode 15 on a bottom glass substrate 14.
Referring to FIG. 1, the background art PDP is provided with the top glass substrate 10 for displaying an image, the bottom glass substrate 14 spaced from, and disposed in parallel with the top glass substrate 10, a plurality of partition walls 16 disposed between the bottom glass substrate 14 and the top glass substrate 10 at fixed intervals, and a plurality of discharge spaces formed by jointing of the top glass substrate 10 and the bottom glass substrate 14. The PDP is provided with an address electrode 15 on the bottom glass substrate 14 between each of the plurality of partition walls 16, a fluorescent film 17 formed on both sides of the partition walls 16 and on the bottom glass substrate 14 to cover the address electrode 15 in an internal surface of each of the discharge spaces for emitting a visible light on discharge, and transparent electrodes 8 and 8' and bus electrodes 9 and 9' formed alternatingly at fixed intervals on the top glass substrate 10 at a surface facing the bottom glass substrate 14. The transparent electrodes 8 and 8' and the bus electrodes 9 and 9' are formed on a central part of the bottom glass substrate 14 perpendicular to the address electrode 15, dividing a screen of the PDP into a plurality of cells. And, there are a dielectric film 12 on the transparent electrodes 8 and 8' and the bus electrodes 9 and 9' for restricting a discharge current and a protective film 13 on the dielectric film 12 for protecting the transparent electrodes 8 and 8', the bus electrodes 9 and 9' and the dielectric film 12, and a mixture of inert gases, i.e., helium He as a major gas added with xenon Xe and neon Ne filled in each of the discharge spaces at 400.about.500 torr. The mixture gas induces penning effects when discharge in the cells.
A process of image display on the unit cell of the aforementioned background art PDP will be explained.
Upon application of a discharge voltage to the sustain electrodes 11 and 11' to cause a surface discharge, space charges generated in the cell accelerate micron electrons in the discharge gas to collide on neutral particles, which causes another collision, accelerating ionization of the neutral particles, converting the discharge gas into a plasma and emitting a vacuum ultraviolet ray. This vacuum ultraviolet ray excites the fluorescent film 17, to generates a visible light, which is shot outwardly through a display surface of the top glass surface 10. Thereafter, by keeping the application of the sustain voltage to the transparent electrodes 8 and 8' for a certain time period, a sustained discharge between the sustain electrodes 11 and 11' is caused, and by keeping each cell luminous for a certain time period, an image can be displayed.
FIG. 2 illustrates a plan view of a top electrode in a background art PDP.
Referring to FIG. 2, the PDP is provided with a plurality of partition walls 16 and one pair of transparent electrodes 8 and 8' and bus electrodes 9 and 9' formed at fixed intervals on a top glass substrate perpendicular to the partition walls 16. One pair of sustain electrodes 11 and 11' having the transparent electrodes 8 and 8' and the bus electrodes 9 and 9' include one pair of tooth formed projections 20-1 and 20-2 perpendicular to an address electrode(not shown) on a bottom glass substrate(not shown) and causes an entire screen divided into a plurality of cells. The pair of sustain electrodes 11 and 11' are formed of deposition of indium oxide InO.sub.2 or tin oxide SnO.sub.2, which are transparent. The tooth formed projections 20-1 and 20-2 are formed opposite to each other with a gap of 50 .mu.m.about.80 .mu.m.
The operation of the aforementioned background art PDP will be explained additionally referring to the elements that is omitted from FIG. 1.
Upon application of a sustain voltage to the sustain electrodes 11 and 11', wall charges are generated at ends of the pair of tooth formed projections 20-1 and 20-2, which cause a surface discharge within the discharge cell. The surface discharge causes another surface discharge in a discharge region 18 at surfaces of the dielectric film 12 and the protection film 13, that, in turn, generates a vacuum ultraviolet ray 19 which excites the fluorescent material in the fluorescent film 17, exhibiting a color.
However, since a structure of the top glass electrode in the background art PDP does not allow to secure a large discharge region between the sustain electrodes, implementation of a color PDP of a high luminance has been difficult.